Arrangement for eliminating disturbances in receiving sound waves



June 4, 1929, Y w, HAHNEMANN 1,715,831

ARRANGEMENT FOR ELIHINATING DISTURBANCES IN RECEIVING' SOUND WAVES FiledJuly 21. 1921 I n im Patented June 4;', 1929.

UNITED STATES AVVAL'IIIEIB. HAHNEMANN, 0F KITZBERG, NEAR KIEL, GERMANY,ASSIGNOR TO SIGNAL' I GESELLSCHAFT M. B. H., F KIEL'GERMANY.

.ABRANGEMENT FQR ELUIINATING DISTURBANCES RCEIVIN G SOUND WAVES.

Application led Julyn '21,' 1921, Serial No. 486,568, and in GermanyAprily 3, 1920.4

This invention relates in general'to an arrangement for eliminatingdisturbances in receiving sound waves, or noises which posv Sess thecharacteristics of a tone of any kind.

The invention relates more articularl to an arran ement for eliminatmgdistur ing sounds w en receivingsound signals with the aid of submarinesound receivers in which the sound that is received by a radiating.member (such as a diaphragm) abutting on the water is transmittedthrough an air chamber to the sound conductor leading to the operatorsposition. The said eliminating arrangement consists in interposing, inthe '15 path along which the sound travels from the radiating member tothe ear of the operator,`

achamber adapted to cooperate with a member tuned to the sound tobereceived and equi ped with a' sound damping means. To

zo ren er a chamber of thiskind more eiective it is tuned in accordancewith the'invention to the frefpiency of vibration of the signals to bereceived. An. advantageous manner' of tuning the said chamber consistsin propz5 erly dimensioning its length.

The invention 1s illustrated in the drawing in which Fig. 1 is adiagrammatic longitudinal seeton of a receiving device with a disturblance-eliminating-chamber arranged to cooperate with a diaphragm attachedto a microphone,

Fig. 2, is a similar representation except that thedisturbance-eliminating chamber cooperates with a spherical resonator,and

Fig. 3 shows a receiving device with an eliminating chamber providedwith adjust'- able lateral perforations for tuning purposes.

The arrangements shown in the three ligu res each comprise a radiatingmember or sound receiving diaphragm 1 that abuts on the external soundpropagating medium through which the sound waves arrive. Adjoining thediaphragm 1 is a chamber 2 filled .15 with air and preferably ofextremely small size. This chamber 2 acts as an acoustic link or soundtransferring means.y In Figs. 1 and 2 the disturbance-eliminatingchamber 4 connected to the chamber 2 is the next acoustic link in thechain of soundv transferring members. In the devices illustrated thesound waves that pass through thechamber" 4 are damped by a linin 5` inthis chamber -composed of sound absor in material (for example, felt).Adjoining e chamber 4 in Fig. 1 is a vibratory diaphragm 6 which istuned to the sound to be received and carries a microphone 7. The latteris connected by wires 8 and 9 to the telephone receiver 14.

In the modification illustrated in Fig. 2 the 60 chamber 4 at the rearterminates. in' a rigid A plate. Through an opening 10 in this plate thechamber. 4 is connected to a spherical resonator 11 to which is joinedthe sound conductor or pipe 12 that conducts the sound to the `operatorsposition 15. v

` In Fig. 3 the sound pipe 12 is located between the external receiver1, 2, 3 and the damping chamber 4. In this latter the disturbingvibrations are eliminated not'only by a-damping lining 5 but also byholes 13 which, particularly in cases of low tones, are very effective.The perforations 13 may be divided into groupsof various sizes and aslide valve may be provided by which the perforations may be changedaccording to the frequency of vibrations of the disturbing sounds.

The field of application for such means for ltering or sifting outdisturbing vibrations is, of course, exceedingly large. They arespecially important in cases where tones, or noises resembling tones,are received from water; because 1n such cases, particularly on accountof the ear not being accustomed to distinguish between different soundspropagated through water, the elimination of disturbances'is especiallyimportant. Itwill be obvious that a plurality of such devices may beused in one and the same sound-conductor '90 or chain of -acousticlinks. By dimensioning thesound eliminating chamber in a s ecial way theelimination of certain requencies of vibration or certain groups of suchfrequencies can be made to be more pronounced.

The term vibratory body, as used in the claims, is intended to cover notonly a body such as a diaphragm but also a body of gas; while the termtuned is intended tomean that the tuned body operates in its naturalfrequency.

I claim 1. A sound receiving arrangement, comprising a sound receivingmember abutting on the sound propagating medium, an operators observingdevice, and sound ltering means .interposed in the sound path betweenthe chamber having auxiliary means for dissipating undesired vibrationsand a tuned vibratory body cooperating with said chamber.

2. A sound receivlng arrangement, comprising a sound receiving memberabutting on the sound propagatin medium, an operators observing device,an sound filtering means interposed in the sound path between said soundreceiving member and the observing device, the sound filtering meanscomprising a chamber having auxiliary means for dissipating undesiredvibrations and a tuned diaphragm cooperating with said chamber.

3. A sound receiving arrangement, comp rising a sound receiving memberabutting on the sound propagating medium, an operatois observing device,and sound filtering means interposed in the sound path between the soundreceiving member 'and the observing device, the sound filtering meanscomprising a chamber .having auxiliary means for dissipating' undesiredvibrations and a tuned diaphragm cooperating with said chamber, and amicrophone cooperating with said tuned diaphragm.

LA sound receiving arrangement, comprising a sound receiving memberabutting on the sound propagating medium, an operators'observing device,and sound filtering means interposed in the sound path between the soundreceiving member and the observing device, the sound filtering meanscomprising a chamber having a sound absorbing wall for dissipatingundesired vibrations and a tuned vibratory body cooperating with saidchamber.

5. A sound receiving arrangement, comprising a sound receiving memberabutting on the sound propagating medium, an operators observing device,and sound filtering means interposed in the sound path between the soundreceiving member and the observing device, the sound filtering meanscomprising a tuned chamber having auxiliary means for dissipatingundesired vibrations.

6. A sound receiving arrangement, comprising a sound receiving memberabutting on the sound propagating medium, an operators observing device,and sound filtering means interposed in the sound path between the soundreceiving member and the observing device, the sound filtering meanscomprising a 4tuned chamber having a sound absorbing wall and providedwith perforations.

7. A sound "receiving arrangement, comprising a sound receiving memberabutting on the sound propagating medium, an operators observing device,and sound filtering means interposed in the sound path between the soundreceiving member and the observing device, the sound filtering meanscomprising a tuned chamber having a sound absorbing wall and providedwith perforations and means for varying the extent of said perforations.

8. A sound receiving arrangement, com'- prising a sound receiving memberabutting on the sound propagating medium, an operators observing device,and sound filtering means interposed in the sound path between saidsound receiving member and said observing device, the sound filteringmeans comprising a tuned chamber having auxiliary means for dissipatingundesired vibrations and a' tuned vibratory body cooperating with saidcham- 9. A sound receiving arrangement, comprising a sound receivingmember abutting on the sound propagating medium, an extremely small andflat gas Vchamber adjoining the' said receiving member, an operators'observing device, and sound filtering means interposed in the soundpath between said gas chamber and said observing device and comprising atuned body including means for dissipating undesired vibrations.

10. A sound filtering device, comprising a tuned body including meansfior dissipating undesired vibrations. 'Y A 11. A sound filteringdevice, comprising a tuned resonating chamber yprovided with aperturesfor dissipating undesired vibrations.

12. A sound filtering device, comprising a tuned resonating chamberprovided with a sound absorbing Wall and with apertures for dissipatingundesired vibrations.

13. A sound filtering device, comprising a chamber having means fordissipating undesired vibrations, and a tuned diaphragm in soundtransferring relation with said chamber.

14. A sound filtering device,.comprising a tuned resonating chamberhaving auxiliary means for dissipating undesired vibrations, and a tuneddiaphragm in sound transferring relation with said chamber.

, In testimony whereof I affix my signature.

WALTER HAHNMANN.

